Magnetic brake device



Jan. 27, 1931.

s. '6. DOWN MAGNETIC BRAKE DEVICE Filed Sept. 22, 1927 24 as I? q 7 I0 20' I J f g a l A VINVENTOR SIDNEY G.DOWN BY ATTOR Y Patented Jan. 27 1931 UNITED STATES;

SIDNEY G. DOWN, or nnenwoon, rENNsYLvi-aivra, ,Assre von 'rotrnn wnsrmeriousii AIR BRAKE COMPANY, or wrnmnnnmq, rnimsYLv nr conro mrroiv or IPENNSYLVANIA MAGNETIC 'ssiamsvm Application filed September 22, 1921' emim 1'ie t.

This invention relates to the type of railway brake, in which a magnetic brakeshoe is normally held suspended away from the rail, and is adapted upon energization to be attracted to the rail and therebyact as a brake.

In order to apply the brakes, the inagneti'c pull exerted by the brake shoe magnet must be sufiicient to cause movement of the brake shoe through the gap or clearance space nor- 7 mally existing between the shoe and therail.

vention.

As the shoe approaches the rail, the magnetic attractionvincreases and the result in that the shoe engages the rail suddenly and causes a grabbing effect, this effect being more pronounced as the gap or clearance space is 1ncreased due to wear of the brake shoe and the like.

ing a magnet coil 2 and being suspended over the rail 3 by means of a rod 4; They piston 5 is secured to the upper end of the rod 4 and said piston is contained in a cylinder 6, which is suitably mounted on the vehicle.-

A coil spring 7 is disposed in the chamber 8 and acts on the piston 5, so as to normally maintain the brake shoe 1 in its suspended position. Also mounted on the vehicle isv a V valve device comprising a casing 9, contain-c ing a valve piston 10. Said valve piston is provided with a seatadapted to engage an annular seat rib 11, and a pipe 12 opens'to the space within the seatrib, said pipe being either connected to the straight air pipe of a fluid pressure brake system, or to the usual brake cylinder 28.

The valve piston 10 is urged to its seat by a coil spring 13 and the chamber 14; at the toan atmospheric port 15;, 7 The chamber 16 outside ofthe seatrib 11 spri'ng side of the valve piston is connectedis connect'ed to a pipe 17 which leadstopise ton chamber 18, anda vent passage 19 con;

valve piston ilt) is seated. i

A switch device for controlling the circuit of the'brake shoe magnet 2 'isalso provided, comprising a casing 20 containing a valve piston 21 adapted to seat on a's eat ribfl22, the spacewithin the seatribfbeing connected pipe 17.

1 V .7 nects'chamber 16 with chamber 1 .1, when the A-c'oil springs?) urges memes 15110521 to its seatand said cpiston islprovidedwith a stem 2d carrying 'at'its outerend a switch contact 25, adapted-when moved upwardly from the position shown in the-drawing 'to connectco'ntacts'26 and 27 for closing "acircuit from a source of 'current-f'thr'ough the magnet coil 2. i In operation, when'the' operator initiates an application of the fluid pressure brakes,

fluid under pressure is suppliedto pipe '12,-

either from the'brake cylinderor from the straight air brake pipe.

The valve piston 10, is unseated by pres sure offluid supplied through pipe 12 tothef space within the seat rib 11' and when unseated, the iull'area of the piston being exposed, the valve piston is quickly moved to its o ter Position; ,i

- Fluid under pressure then supplied from chamber 16 through pipe 17 to piston chamberlS and the piston 5 is thereupon actuated so as to move the brake shoe 1 into engage ment with the rail 3 and cause a braking effect on the vehicle by the frictional engagement of the shoe with the rail.

Owing to the restricted area of the switch piston 21 which is open'to .thepressure in pipe 17 when the piston is seated, and the resist ance of the spring 23, the piston 21 will not move until the piston 5 has been shifted to cause the. brake shoe to engage the rail, 3 The pressure of fluid from pipe 17 then increases sufficiently to cause the piston to move the piston 21;,being then exposed to the fluid pressure supplied'through pipe 17, the piston away from the seat rib 22 and the full area of I is quickly shifted to its outer position, in which a circuit is closed from asource of current through the magnet coil 2. The magnetic brake shoe is thus energized so that the brake shoe is pressed against the rail with a force corresponding with the current flow through the magnet coil 2.

1 When fluid under pressure is releasedfrom pipe 12 in releasing the brakes, the fluidpressure below the valve piston 10 alsoreduced and when reduced to a predetermined degree,"

the valve piston 10'is moved back toengage the seat rib 11 by the spring 13. The reduc 7 tion in pressure in pipel? first causes the movement of piston'Ql, since the magnetic" pull of the brake shoe 1 resists the upward movement of piston 5. The downward movement of piston 21 causesthe switch contact-25 to move so as to open the circuit of the magnet coil 2,and themagnet coil being thus deenergized, the piston 5 is moved upwardly by the spring 7; Fluid under pressure remaining in the pipe 17 after the valve piston 10 moves to its seat is vented through passage 19 to the atmospheric port 15. 1

While oneillustrative embodiment of the invention has been described in detail, it is not my intention to limit its scope to thatembodiment orotherwise than by the terms of the appended claims. i 7

Having now described my invention, What I'claim as new and desire to secure by Letters Patent, is

1. In a vehicle brake, the combination with a magnetic brake shoe normally held out of engagement with a friction surface, of means for moving the shoe to the friction surface while the shoe remains deenergized and for then energizing said shoe.

2. In a vehicle brake, the combination with a magnetic brake shoe normally held out of engagement with a friction surface, of means operated by fluid under pressure for moving the shoe to the friction surface and means operated by fluid under pressure for then closing a c1rcu1t for magnetizing said shoe.

In testimony whereof I have hereunto set I myhand; I y

- SIDNEY DOWN. 

